The largest and most provocative of the studies focused on whether breakfast plays a role in weight loss. Researchers at the University of Alabama at Birmingham and other institutions recruited nearly 300 volunteers who were trying to lose weight.
They randomly assigned subjects to either skip breakfast, always eat the meal or continue with their current dietary habits. (Each group contained people who habitually ate or skipped breakfast at the start, so some changed habits, and others did not.)
Sixteen weeks later, the volunteers returned to the lab to be weighed. No one had lost much, only a pound or so per person, with weight in all groups unaffected by whether someone ate breakfast or skipped it.
In another new study this one of lean volunteers researchers at the University of Bath determined the resting metabolic rates, cholesterol levels and blood-sugar profiles of 33 participants and randomly assigned them to eat or skip breakfast. Volunteers were then provided with activity monitors.
After six weeks, their body weights, resting metabolic rates, cholesterol and most measures of blood sugar were about the same as they had been at the start, whether people ate breakfast or not. The one difference was that the breakfast eaters seemed to move around more during the morning; their activity monitors showed that volunteers in this group burned almost 500 calories more in light-intensity movement. But by eating breakfast, they also consumed an additional 500 calories each day. Contrary to popular belief, skipping breakfast had not driven volunteers to wolf down enormous lunches and dinners but it had made them somewhat more sluggish first thing in the morning.
Together, the new research suggests that in terms of weight loss, breakfast may be just another meal, said Emily Dhurandhar, the assistant professor at the University of Alabama at Birmingham who led the study there. Skipping breakfast in these studies, she said, did not fatten people.
Each study was fairly short-term, however, and involved a limited range of volunteers. More randomised experiments are needed before we can fully understand the impact of breakfast, said James Betts, the professor who led the study of lean people. It's not yet clear, for instance, whether heavy peoples bodies respond differently to morning meals than lean peoples, or if the timing and makeup of breakfast matters.
For now, the slightly unsatisfying takeaway from the new science would seem to be that if you like breakfast, fine; but if not, dont sweat it. I almost never have breakfast, Dr Betts said.
That was part of my motivation for conducting this research, as everybody was always telling me off and saying I should know better. Based on the results of these studies, he said his habits wont change.
Neither will those of Dr Dhurandhar, who enjoys a morning meal. But, she said, I guess I wont nag my husband to eat breakfast anymore.
- Gretchen Reynolds